Parting & Grooving
Many components have an internal groove, most of them are close to the entrance into the hole e.g circlip grooves. The most common method to produce internal grooves is by radial grooving but also multiple grooving and plunge turning can be used, see
methods of turning grooves
CoroCut with dedicated geometries GF, GM, TF and TM to be used for internal operations. For small diameter bores down to 12 mm, the Q-Cut 151.3 with geometry 4G can be used. The CoroCut MB is available in solid steel and solid carbide bars for better stability in longer overhangs. The precision grooving insert is available in widths from 0.7–3 mm.
For real small diameters 4.2 mm, the CoroTurn XS system has insert widths in the range of 0.78–2 mm.
During chip evacuation there is a large risk of chip jamming resulting in tool breakage, especially when grooving into small holes. The chips have to be removed from the groove, change direction 90°, pass the side of the toolholder and finally removed from the hole.
For secure chip evacuation, it is necessary to have a large deviation between hole diameter and bar diameter hence a small diameter bar is the best option. Unfortunately there is a high risk of vibration with small diameter bars.
Stability is the key to avoid vibration and this is related to the tool overhang and how far into the hole the groove is machined. The risk of vibration is avoided by using the largest bar size possible, while chip jamming avoidance call for the opposite.
The overhang should not exceed 3 x
for solid steel and 5 x
for solid carbide boring bars. With damped boring bars it is possible to cut with overhang up to 5 x
and with a carbide reinforced damped bar up to 7 x
Methods of turning grooves
Parting and grooving systems
Tailor made inserts
Recommended grade and cutting data
Starting grade GC1125.
Cutting speed 125 m/min and feed 0.07 mm/r.
Use EasyFix clamping sleeves for accurate machining with less vibration and precise height.
Carbide reinforced damped bars
Damped and carbide bars
Solid steel bars
Operation: Internal circlip grooving
Material: Stainless steel 316L, CMC 05.2
Machine: CNC turning lathe
Tool holder: RAG123G09-32B
Time in cut:
Tool life +73%
Annual time saving 60 hours
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© Sandvik Coromant
09/03/2010 01:14:53 PM
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